Noise from USB charger even with engine off?!

[legacyshawn]

I'm using the 2.1amp USB charger port to power a media player for my nav screen and I seem to be getting noise on the display and through the speakers when it's plugged in. I had a wall adapter putting out the same amps at 5 volts though a car inverter without any noise..now with the car charger I get noise like a ground loop with alternator noise but I get the same noise in the speakers and the screen even with the car off.

 

Is there a small product I can use in line between the charger and the media player that could regulate the voltage or suppress sound from the USB power port?

 

This is the charger

[ame=http://www.amazon.com/gp/aw/d/B00H2ZU72W]TopG [Lifetime Warranty] Dual USB Ports 3.1A Portable USB Car Charger for iPhone 5 5S 5C 4 4S,iPad 4 3 2,iPad mini,iPad air Battery Power Supply for All Apple Device (Lightning Cable/Adapter Not Included)- (Black+Silver):Amazon:Cell Phones & Accessories[/ame]

And the media player

http://www.miccatron.com/micca-speck/

[theflystyle]

Sounds like a possible grounding issue.

[legacyshawn]

Yeah but noise with the engine off?

[compsurge]

Absolutely. It likely does not have a built-in ground loop isolator. The DC/DC converter is generating the noise and is backfeeding your audio electrical system.

[RedFloyd]

Some chead 12V - 5V converter generate some high frequency noise that can be heard in the audio signal. This noise is caused by the switch mode converter inside the converter. A good desing won't generate any noise.

 

You can try to add a filter on the 5V supply (inductor - capacitor). It may help a little. Also, try to have the shortest connection as possible.